Last Friday brought big news to the world of physics: at a meeting in France, scientists from 57 countries voted to replace the famous object known as Le Grand K with a new system of defining the kilogram. This change was a long time coming, and as the physics community has prepared for it over the years, Scientific American has been there to cover the topic. The following graphic from the archives shows how scientists went about redefining the kilogram.

Credit: Jen Christiansen

And the graphic below, from 2017, below puts the redefinition in context of a larger planned overhaul of the International System of Units.

Credit: Nigel Holmes